What does it take for a county to be a bellwether?
Let’s turn the clock back to 1988.
For a county to be considered a bellwether it would have to vote for the winning party at each of the following elections:
1992 Democrat switch
2000 Republican switch
2008 Democrat switch
2016 Republican switch
That is 4 switches in 8 election cycles! Out of 3,141 counties, there were 22 counties that had successfully voted for the winning candidate in each and every election between 1988 and 2016 (included).
If bellwethers were just a “statistical curiosity” and purely random, we could expect half of these counties to pick the winning party at the 2020 election.
But there was only one county – Clallam, Washington – which voted Democrat. All other 21 counties voted Republican.
It is easy to gloss over this. We already claimed that bellwether counties are a lot more than “statistical curiosities”, but let’s assume for the time being that normal rules of probability apply…
If you take a coin and flip it 22 times. What are the odds of getting 21 “heads” or 21 “tails”?
The probability is hard to comprehend, so let’s figure it out for real. Let’s find a coin, and flip it.
Really … stop reading. Find a coin, and flip it, and see how long it takes to (just) get 10 heads or 10 tails in a row.
Or even better, if you have children, get them to do it for you. It will keep them entertained for hours, and you can tell them it is for a good cause. After you have spent an hour trying, record the maximum streak length you achieved.
You should now have a real tangible sense of how difficult it is to get a streak of 10. Now imagine getting 21 out of 22…!
Furthermore, consider the fact that bellwethers don’t just have a random 50% chance at winning — we should expect them to have a better than 50% chance of getting it right.